The excerpt represents the core issue or deciding factor on which you must meditate, and is drawn from The Voyage of the Beagle by Charles Darwin: ----------------------------------------------------------------
Equatorial region; mean result 15,748 Humboldt.
Bolivia, lat. 16 to 18 degs. S. 17,000 Pentland.
Central Chile, lat. 33 degs. S. 14,500 - 15,000 Gillies, and
the Author.
Chiloe, lat. 41 to 43 degs. S. 6,000 Officers of the
Beagle and the
Author.
Tierra del Fuego, 54 degs. S. 3,500 - 4,000 King.
As the height of the plane of perpetual snow seems chiefly to
be determined by the extreme heat of the summer, rather than
 The Voyage of the Beagle |